Abstract: Apparatus and method for altering computational constants stored in an EAROM of a microwave oven microcomputer. In the normal or operational mode, the microwave oven control panel is used by the operator to enter control data for the microwave oven. After a mode determining signal is applied to the microcomputer by grounding one of its specified ports, new computational constants can be entered through the control panel and stored in the EAROM so as to alter the operating characteristics of the oven.

Abstract: A refrigerator having a crisper pan with a back passageway that is always open and a front passageway that is adjustable so that the operator can adjust the amount of flow through ventilation to control the humidity in the pan. The lid for the pan also functions as a refrigerator shelf and the back passageway is defined by a gap between the lid and the back of the pan. The front passageway is defined by a front lid plenum having a floor with a plurality of ports. A slide gate positioned in the plenum has a plurality of windows which, by sliding laterally in the plenum, can be made to respectively align with the ports to enable flow through ventilation. Full or partial sealing of the ports is provided by sliding the slide gate laterally to alter the alignment of the windows with the ports.

Abstract: A microwave oven cavity air flow system having a grease shield adapted for receiving a nominal flow of air and efficiently using that flow to rotate the antenna and to remove moisture from the cavity. The air is first concentrated into a directive stream which impinges the vanes of the antenna rotating structure. Then, the air is directed into a dispersed flow towards the front of the grease shield wherein a first portion is directed down along the door and a second portion is directed back along the underside of the grease shield to directly transfer water vapor rising from the food to a rear exhaust. The grease shield has a channel for receiving an antenna mounting cradle.

Abstract: A microwave oven having a low friction bearing support for a rotatable microwave feed assembly which includes a primary radiating antenna axially coupled to a cylindrical metal stub that vertically extends from the microwave cavity through an aperture into the waveguide where it is excited by microwave energy. The stub has a bottom cylindrical bore which inserts over a microwave transparent post that extends upwardly through the aperture from a horizontal cross bar suspended by two legs connected to the cavity ceiling. The cross bar may be oblique to the waveguide to centrally and positively align the post in the aperture. The roof of the bore has a downward spherical surface which provides a low friction bearing with the microwave post. The feed assembly also includes a microwave transparent turbine against which a stream of air is directed to rotate the feed assembly.

Abstract: A refrigerator having a reversible cold air meat keeper for providing convenient access thereto regardless of the side of the refrigerator that the doors are hinged. The cold air is channeled into a plenum behind the back wall of the refrigerator compartment and there are at least two spaced ports communicating from the plenum into the chamber. The cold air meat keeper has a conduit extending from the rear wall thereof. In one predetermined mounting position of the meat keeper, the conduit removably couples with one of the ports for receiving cold air from the plenum. In the alternate predetermined mounting position of the meat keeper, the conduit removably couples with the other port for receiving cold air.

Abstract: An air conditioner having an improved fresh air path from the outward compartment into the evaporator blower wheel. The evaporator blower motor is mounted on the outward side of the main partition and is spaced from the evaporator blower wheel by an air chamber that has a vent communicating with fresh air. Accordingly, the fresh air enters the evaporator blower wheel from the air chamber which is on the opposite side of the evaporator blower wheel from which the recirculation air enters. The more direct fresh air path provides a higher positive draft thus creating a higher percentage of fresh air in the mixture.

Abstract: A method for defrosting in a microwave oven wherein maximum or 100 percent power is applied until the surface temperature of the food reaches 110.degree. F. and the the power is reduced to a level which holds the surface at 110.degree. F. until the food is defrosted. The time periods are calculated in a microcomputer in accordance with the weight which is provided by an oven based scale. The reduced power level is either 10 percent or 20 percent as determined by the food category as input to the microcomputer by the operator.

Abstract: Microwave oven scale apparatus for coupling weight from the cavity and for providing a weight corresponding signal. The weight corresponding signal is used by a microcomputer to compute cooking times. Microwave transparent posts insert through holes in the floor of the cavity and support a tray on which the food is positioned. The posts respectively screw down on unitary studs that have legs which straddle a pivot member of the scale. The height of the studs can be adjusted by rotation on the studs. The studs are aligned vertically and horizontally by connection to a frame positioned below the cavity floor. The scale includes two parallel rails that are pivotally supported on their outward edges and have inwardly directed extender arms which couple together at a location where they are supported by a compliant member.

Abstract: A metal rod rack shelf for a microwave oven wherein extension support rods are substantially prevented from being excited with high electric currents. The rack is embodied with quarter wavelength choking structures in the regions where the extension support rods connect to the rack mainframe. Accordingly, the effective short circuits in those regions are transformed to open circuits at a distance of one-quarter wavelength along the support rods. As a result, the support rods do not rise to high temperatures or radiate intense microwave fields that could cause melting of or arcing to microwave transparent brackets which mount to walls of the oven cavity and engage the rods.

Abstract: A method for controlling a microwave oven with a microcomputer wherein a first time period corresponding to the time required to raise the temperature of a weighed food body from refrigerator temperature to room temperature and a second time period corresponding to the time required to cook the food body from an initial room temperature are calculated and stored. The microcomputer then sequentially controls the magnetron through cycles in accordance with the first and second time periods, respectively. Rather than being erased after completion of the first cycle, the first time period remains stored in the microcomputer and can be activated by the operator to provide a small incremental amount of heat to the food body after it has been cooked. Also, the operator can adjust the number of heat units per weight units used in the calculation of the cooking cycle so as to provide a food body that is cooked less or more than medium doneness.

Abstract: A coupling between a stainless steel exhaust manifold of a recuperative heat exchanger and a plastic flue pipe. The internal integrity of the manifold is maintained by spot welding a mounting bracket to the outside thereby defining a slot between parallel portions of the bracket and the manifold. The flue pipe inserts through coaxial circular apertures in the bracket and the manifold. A shoulder of an annular protrusion on the outside of the flue pipe presses against an O-ring seated in an inwardly directed step of the circular aperture in the manifold thereby providing an airtight seal. The flue pipe is secured in the described position by a bifurcated retainer clip slid down into the slot thereby engaging portions of the opposite shoulder of the annular protrusion.

Abstract: A heater module having a cylindrical heat exchanger surrounding a central cavity and burner wherein an end manifold is covered with a layer of insulation to reduce the temperature differential between the outer annular trough of the manifold and the inner central flat disk which covers the end of the cavity. The annular trough and the disk are stamped from a unitary piece of plate steel. Without the insulation, the disk would heat to a temperature much higher than the annular trough because the trough communicates with tubes of the heat exchanger and contains recirculating liquid. By reducing the temperature differential, less strain is put on the end manifold as a result of nonuniform expansion.

Abstract: Antenna for use with food product in a microwave oven, where one or more antennas are positioned into the food product for efficient and distributed heating of food product. The antenna includes a coaxial assembly of an inner conductor and an outer conductor with dielectric therebetween. A load end, configured as a probe, positions into the food product. A source end antenna element structure delivers power to the load end and subsequently to the food product. The structure at the source end may include a probe center conductor as well as gain antenna structures. The outer conductor may likewise be configured including ground plane disc, a folded-over coaxial outer conductor or the like.

Abstract: A recuperative furnace and method for heating wherein the recirculation air blower directs the return air upwardly first to a recuperative heat exchanger and then to a second heat exchanger operating from the heat of combustion. The flue gases are routed directly to the recuperative heat exchanger where a portion of the products of combustion condense. Accordingly, the recuperative heat exchanger not only provides sensible heat transfer from the flue gases but also recovers a portion of the latent heat of vaporization. The second heat exchanger transfers heat from a solution to the recirculation air. The solution flows through a closed loop between the second heat exchanger and a heat transfer module which includes the burner.

Abstract: A microwave oven having a directional rotating antenna axially supported on an axis of one wall of a microwave oven cavity of the microwave oven which provides circularly symmetric uniform energy distribution of microwave energy within the microwave oven cavity and consistent heating of a product in the microwave oven cavity. The directional rotating antenna includes a two-by-two array of antenna elements where each element is an end driven half-wavelength resonating antenna element supported by a length of conductor perpendicular to the wall of the microwave oven cavity. A parallel plate transmission line connects to each of the supports, four of which join at a junction which connects to a cylindrical probe antenna. The probe antenna is excited by microwave frequency currents of a waveguide adjacent to the wall of the microwave oven cavity. The directional antenna is rotated by a moving stream of air circulated through the microwave oven cavity.

Abstract: A system of combining a microwave oven and ventilator over a range top or the like wherein the ventilator comprises an assembly including a central oven receiving compartment and air handling components providing for an exhausting of the range top atmosphere and a maintenance of the oven in a relatively contamination free environment. The ventilator includes a downwardly directed filter-mounting cavity underlying the oven. A pair of vertically extending air directing channels are provided to each side of the oven receiving compartment and extend vertically from communication with the underlying cavity to a pair of chambers located above the oven compartment and in direct communication with an exhaust blower positioned centrally therebetween. The exhaust blower is communicated with the ambient atmosphere above the oven compartment for introduction of cooling uncontaminated air.

Abstract: A windowed door assembly for a combination microwave and hot air oven having a choke-coupling type seal formed around the periphery of the window opening to suppress the leakage of microwave energy from the area between the main body of the door and the window portion of the door. The window portion is removably connected to the main body of the door in a region of relatively high capacitive impedance to reduce the importance of the mechanical connection in suppressing the leakage of microwave energy from the oven.

Abstract: A microwave oven cavity of a microwave oven having an antenna assembly axially supported on one wall of the cavity. The antenna assembly includes an antenna rotating assembly having a bushing mounted in the wall, a bearing axially supported in the bushing, a probe antenna supported in a bearing and extending into the cavity, a directional rotating antenna attached to the probe antenna, and an antenna rotor having a plurality of turbine vanes affixed to the directional rotating antenna which axially drive the directional rotating antenna when forced by air flow velocity circulated through the cavity. The antenna rotating assembly, the directional antenna, and the antenna rotor are integrated for installation and removal from within the confines of the cavity. The antenna assembly engages and locks in position in the wall of the cavity.